ProjectMagnetic cataclysmic variables in X-rays: Development of models for X-ray emitting regions
Basic data
Title:
Magnetic cataclysmic variables in X-rays: Development of models for X-ray emitting regions
Duration:
16/11/2026 to 15/11/2029
Abstract / short description:
At present, the known population of cataclysmic variables has grown
greatly, allowing detailed studies of the properties of this population of
objects in the Milky Way to begin. This is due to the extensive survey
works in both the X-ray (SRG/eROSITA) and optical (SDSS, 4MOST,
LAMOST, ZTF) bands, accompanied by the work of the Gaia
astrometric observatory. For a detailed comparison of the results of
population synthesis with observations, among other things, it is
necessary to know the masses of white dwarfs in these systems.
Intermediate polars with observed hard X-ray emission are a subclass
of cataclysmic variables for which fairly reliable determination of white
dwarf masses is possible. The hardness of the X-ray spectrum in
these objects depends mainly on the mass of the white dwarf, though
the magnetospheric radii and the local accretion rates are also
important. In total, the masses of about forty white dwarfs in
intermediate polars have been determined from the shape of their
hard X-ray spectra. Recently, however, there have been observational
indications that the physics of accretion columns requires a more
detailed consideration. In this project, we propose to develop new
physical models of post-shock structures that will describe the X-ray
spectra of intermediate polars with higher accuracy. This allows us to
more accurately determine the masses of white dwarfs in these
objects. In particular, we plan to take into account cyclotron cooling in
tall low-luminosity accretion columns in a more correct way, and
develop physically self-consistent models of Compton reflection from
the white dwarf surface and the bottom of the accretion column. We
also plan to consider the effect of relatively high plasma density on
the thermal cooling rate of accretion columns and their emission
spectra, since the currently used collisional approximation could be
insufficient to describe the plasma of accretion columns.
greatly, allowing detailed studies of the properties of this population of
objects in the Milky Way to begin. This is due to the extensive survey
works in both the X-ray (SRG/eROSITA) and optical (SDSS, 4MOST,
LAMOST, ZTF) bands, accompanied by the work of the Gaia
astrometric observatory. For a detailed comparison of the results of
population synthesis with observations, among other things, it is
necessary to know the masses of white dwarfs in these systems.
Intermediate polars with observed hard X-ray emission are a subclass
of cataclysmic variables for which fairly reliable determination of white
dwarf masses is possible. The hardness of the X-ray spectrum in
these objects depends mainly on the mass of the white dwarf, though
the magnetospheric radii and the local accretion rates are also
important. In total, the masses of about forty white dwarfs in
intermediate polars have been determined from the shape of their
hard X-ray spectra. Recently, however, there have been observational
indications that the physics of accretion columns requires a more
detailed consideration. In this project, we propose to develop new
physical models of post-shock structures that will describe the X-ray
spectra of intermediate polars with higher accuracy. This allows us to
more accurately determine the masses of white dwarfs in these
objects. In particular, we plan to take into account cyclotron cooling in
tall low-luminosity accretion columns in a more correct way, and
develop physically self-consistent models of Compton reflection from
the white dwarf surface and the bottom of the accretion column. We
also plan to consider the effect of relatively high plasma density on
the thermal cooling rate of accretion columns and their emission
spectra, since the currently used collisional approximation could be
insufficient to describe the plasma of accretion columns.
Keywords:
astrophysics
Astrophysik
Involved staff
Managers
Faculty of Science
University of Tübingen
University of Tübingen
Institute of Astronomy and Astrophysics (IAAT)
Department of Physics, Faculty of Science
Department of Physics, Faculty of Science
Other staff
Institute of Astronomy and Astrophysics (IAAT)
Department of Physics, Faculty of Science
Department of Physics, Faculty of Science
Local organizational units
Institute of Astronomy and Astrophysics (IAAT)
Department of Physics
Faculty of Science
Faculty of Science
Funders
Bonn, Nordrhein-Westfalen, Germany